U.S. Pat. No. 2,410,434 issued Nov. 5, 1946 and U.S. Pat. No. 3,902,025 issued Aug. 26, 1975 disclose telephones which include in one component a receiver, a transmitter and a dial or punch button digit output system. Neither of these devices is in the form of a headset and they are not of light weight construction.
U.S. Pat. No. 4,020,297 issued Apr. 26, 1977 and U.S. Pat. No. 4,039,765 issued Aug. 2, 1977 both disclose headsets with adjustable microphones. Neither of these two references discloses a system having a keyboard with digits arranged to control output signals.